Ruptured Huge Internal Iliac Artery Aneurysm in an Elderly Adult

An 83-year-old man with a medical history of hypertension was sent to the emergency department with a 2-day history of dyspnea and abdominal distension. His pulse was 86 beats per minute, and blood pressure was 112/68 mmHg. On physical examination, he looked acutely ill and had mild dyspnea and distension in his lower abdominal area without peritoneal signs. Blood tests showed hemoglobin of 9.8 g/dL, platelet count of 15,400/mL, and creatinine level of 2.34 mg/dL. Abdominal radiograph showed no abnormalities. Emergency abdominal computed tomography (CT) showed a huge, isolated, right internal iliac artery aneurysm approximately 12 cm in diameter and contrast medium extravasation in the lower abdomen (Figure 1). A cardiovascular surgeon was consulted, but the man died from a ruptured internal iliac artery aneurysm (IAA) on the same day. Internal IAAs are rare, and isolated internal IAAs are even rarer, accounting for 0.04% to 0.4% of all intra-abdominal aneurysms.1 The prevalence has been estimated to be even lower (0.03%) based on a large series of autoptic data.2 Internal IAAs are rarer than other aneurysmal diseases, accounting for 0.4% of all aneurysmal diseases.3 More than 65% of IAAs are thought to occur at multiple sites. (The vast majority involve the common iliac artery; approximately two-thirds of IAAs involve two or more segments of the iliac arterial pedicle, and in one-third of these cases, they occur bilaterally.)4, 5 The cause of aneurysms is most commonly atherosclerotic, whereas other causes (infections, pregnancy, collagen vascular disorders such as Marfan syndrome) are much less frequent. Individuals with IAAs are typically men aged 65 to 70, but presentation from aged 26 to 92 has been described (mean 69 years), as well as cases in neonates and young women. It is much more common in men, with a male to female ratio reported in most studies of 6:1 or greater.6, 7 The vast majority of IAAs are atherosclerotic aneurysms occurring predominantly in elderly men. Occasionally they are pseudoaneurysms that are complications of previous vascular anastomosis, hysterectomy, drainage of ischiorectal abscesses, lumbar disk surgery, hip replacement, or pelvic fractures.2 Like other intraabdominal aortic aneurysms, smoking, hypertension, atherosclerosis, and male sex are clinical risk factors for the development of IAAs. In most cases, IAAs are an incidental finding during ultrasound, computed tomography, or angiography, because they do not always produce symptoms. Common clinical manifestations depend on their cause, size, and location; they may be related to rupture or compression and erosion of surrounding structures (e.g., recurrent urinary infections from urethral obstructions, pain on defecation secondary to rectal compression, paresthesias of the lower extremities due to “nerve trapping phenomenon”).8 In this regard, aneurysmatic vessel size appears to be the most important rupture determinant; in a large series, the average size of ruptured IAAs has been estimated to be 5.6 cm.6, 8 In the case describe herein, the individual died from an acute ruptured IAAs approximately 12 cm in diameter. Isolated internal IAAs are a rare but serious condition of which vascular surgeons need to be aware. Untreated, the natural history is probably one of continued expansion and rupture, with high mortality. Mortality from ruptured IAAs is similar to that from ruptured abdominal aortic aneurysms.9 Conflict of Interest: The editor in chief has reviewed the conflict of interest checklist provided by the authors and has determined that the authors have no financial or any other kind of personal conflicts with this paper. Author Contributions: Min-Po, An-Hsun: concept and design. An-Hsun, Wing-Keung, Min-Po: acquisition of subjects and data. Wing-Keung, Min-Po: analysis and interpretation of data. Min-Po, Wing-Keung, Kuang-Chau: preparation of manuscript. All authors: critical review and approval. Sponsor's Role: None.